P._, “La Ladrerie du porc et le _Tænia solium_,” ‘La France Médicale,’ 1876.--_Putz, H._, “Ueber die Lebenszähigkeit des _Cysticercus cellulosæ_,” &c., ‘Zeitsch. f. pr. Vet.-Wissenschaften,’ 1876.--_Rainey, G._, “On the Structure, &c., of _Cyst. cell._,” ‘Phil. Trans.,’ 1857.--_Rizzetti, G._, “Rendiconto Statistico dell’ufficio d’igiene di Torino per l’Anno 1873.”--_Rudall, J. T._, “Cyst. in the Brain,” ‘Australian Med. Journ.,’ 1859.--_Tartivel, De A._, “Cysticerques multiples dans le tissu cellulaire sous-cutané et dans certain viscères,” ‘Rec. de Méd. Vet.,’ 1876.--_Von Gräfe, A._, in ‘Arch. für Ophthal.,’ 1857.--_Wells, S._, Bourman’s Case, ‘Ophth. Hosp. Rep.,’ 1860.--_Windsor, J._, “Cyst. in the Eye,” ‘Brit. Med. Journ.,’ 1861. _Tænia tenella_, Cobbold.--I have long been acquainted with the fact that there is a comparatively small human tapeworm which cannot be referred to either of the foregoing species. In the absence of experimental proof, I incline to the belief that the worm in question owes its existence to measly mutton. The sheep harbours an armed Cysticercus (_C. ovis_), which I regard as the scolex of _Tænia tenella_. The specific name (_tenella_) was originally applied by Pruner to a cestode six feet in length, which he found associated with a larger tapeworm. This latter he called _Tænia lata_. Whilst Diesing has pronounced Pruner’s _Tænia lata_ to have been a _T. mediocanellata_, I, on the other hand, consider Pruner’s _T. tenella_ to have been a _T. solium_. Mr J. C. Mayrhofer has suggested its identity with _Bothriocephalus tropicus_. When, some years back, I applied the term _T. tenella_ to a new tapeworm (of which I possess several strobiles) I was quite unaware than any similar nomenclature had been adopted by Pruner. From the few facts supplied by Pruner and Diesing, I cannot suppose that our cestodes are identical. Unfortunately my specimens are imperfect, wanting the so-called head. It is not possible to estimate the length of the worm accurately, but the perfect strobile must measure several feet. On one slide I have mounted nine mature proglottides of a worm which I procured on the 15th Dec., 1875. The segments measure, on the average, exactly 1/10″ in length, and only 1/20″ in breadth. The uterine rosettes are all full of eggs, and their branches so crowded together that I am unable to ascertain their average number. The segments are perfectly uniform in character, their reproductive papillæ alternating irregularly at the margin.